DESCRIPTION (Taken from the Investigator's Abstract) Systemic lupus erythematosus (SLE) is a disease with unknown etiology that affects women more frequently than men. The incidence of SLE in American blacks is much higher than in whites, develops at an earlier age, and has increased morbidity and mortality. Significant renal involvement occurs in up to 40% of patients and is, again, even more frequent and more rapidly progressive in blacks. Environmental risk factors for SLE and for renal diseases have been postulated and may play an important role in those patients with SLE who go on to develop lupus nephritis. Previous studies have considered the role of socioeconomic status; serologic measures and MHC genes as explanations of the racial differences, but the role of environmental and occupational factors have not been examined. Using study subjects from the Carolina Lupus Study (CLU) and from the Glomerular Disease Collaborative Network (GDCN), this proposal has two aims: 1. To examine the association between occupational and environmental exposure to nephrotoxic agents, including organic solvents, heavy metals, silica, and smoking, and the risk of developing lupus nephritis; and 2. To determine whether occupational and environmental exposure aggravate the known racial differences in both the incidence and severity of lupus nephritis.